Re: How to construct symmetric matrix from just a one

*To*: mathgroup at smc.vnet.net*Subject*: [mg110419] Re: How to construct symmetric matrix from just a one*From*: Bob Hanlon <hanlonr at cox.net>*Date*: Thu, 17 Jun 2010 02:04:21 -0400 (EDT)

SetAttributes[f, HoldAll]; f[mat_?MatrixQ] := Module[ {n = Length[mat]}, Table[ mat[[r, c]] = mat[[c, r]], {r, n - 1}, {c, r + 1, n}]; m] m = {{1, 0, 0, 0}, {2, 3, 0, 0}, {4, 9, 5, 0}, {2, 2, 3, 4}}; f[m] {{1, 2, 4, 2}, {2, 3, 9, 2}, {4, 9, 5, 3}, {2, 2, 3, 4}} Bob Hanlon ---- dragec <culinovic at gmail.com> wrote: ============= please help me with simple to apply function that will construct symmetric matrix from given just a half matrix with diagonal. Eg: From: 1 0 0 0 2 3 0 0 4 9 5 0 2 2 3 4 To give: 1 2 4 2 2 3 9 2 4 9 5 3 2 2 3 4